Control apparatus for traffic signaling systems



Jan. 18, 1949.

w. M. JEFFER-S 2,459,429

APPARATUS FOR TRAFFIC SIGNALING SYSTEMS CONTROL Filed March 23, 1942.272

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Patented Jan. 18. 1949 CONTROL APPARATUS FOR TRAFFIC SIGNALING SYSTEMSWalter M. Jefiers, Syracuse, N. Y., assignor to Grouse-Hinds Company,Syracuse, N. Y., a corporation of New York Application March 23, 1942,Serial No. 435,770

4 Claims.

This invention relates to a variable speed controller for trafficsignaling systems. Those familiar with the art are well aware of thefact that the trafiic signals in congested areas are operated on aninterconnected system, the control apparatus being such as to operatethe signals at the various intersections of the system in apredetermined timed relation in order to effect the most efficientmovement of traffic in the area. These systems are sometimes termedprogressive systems and operate in such a manner that the signals at theintersections operate progressively one after the other so that platoonsof traffic can travel on the street continuously without being stoppedat any intersection. In order to function in this manner, it isnecessary that the secondary controllers at the various intersections beinterconnected and be supervised by a master timer in order that thepredetermined timed relation between the signals at the variousintersections will be maintained.

In many instances, it is desirable to vary the operation of such systemsduring various times or the day by varying the speed of the secondarytimers. To vary the speed of the secondary timers and at the same timemaintain all such timers of the system in step or predetermined timedrelation, presents a problem of some magnitude. In order to maintain thesecondary timers in step, it is preferable to operate them with asynchronous motor and in systems Where this has been done, it has beenproposed to change the speed of the secondary timers by means ofshifting gears in a gear transmission arranged between the secondarytimers and their respective motors. The gear shifting idea runs intocomplicated and costly structure which frequently ets out of commission.

In lieu of the gear shifting structure, it has been proposed to arrangea friction clutch between the driving motor and the secondary timer andto periodically engage and disengage this clutch from headquarters. Thisclutch arrangement is moreeconomical than the gear shifting,transmission but also results in high maintenance cost and has thedisadvantages of getting the secondary timers out of step with themaster timer and in providing only for the extension of the trafficsignal period by slowing down the timer.

Or, in other words, the speed ofthe timer can not be increased toshorten the total period of the timer. If the gear shifting idea, or theclutch idea, is not employed, it is necessary to have duplicateswitching apparatus associated with each secondary timer and this alsoresults in a complicated and costly structure, it being necessary tohave a switching apparatus for each change of speed desired.

This invention has to do particularly with a trafiic signal controlapparatus for a progressive system, the secondary timers of which areoperated by a synchronous motor, and the invention has as an object aparticularly economical and efiicient means for varying the speed of thesecondary timers.

The invention consists in the novel features and in the combinations andconstructions hereinafter set forth and claimed.

In describing this invention, reference is made to the accompanyingdrawing in which like characters designate corresponding parts in allthe views.

The drawing is a schematic, across the line diagram illustrating myinvention.

For purposes of illustration, I have shown one master timer and onesecondary timer. However, it will be apparent, as the descriptionproceeds, that any number of secondary timers may be included in thesystem.

The master timer consists of a synchronous motor l0 operated by drivingcoil H, one side of which is connected to the hot source ill by wire I3,and the other side to the common return I 4 by wire l5. The motor 18 isoperatively connected to a cam shaft it by means of a variable speedtransmission I l and a reverse gearing Ill. The timer also includes a,second cam shaft I9 connected to the shaft ill by reducing gears 20, 2|,and a change speed transmission 22. A series of earns 23, 24, aremounted upon the shaft l6 and function to operate movable contacts 26,27, 28 respectively, and these contacts are cooperable with stationarycontacts 29, 30 and 3| respectively.

The secondary timer is operated by a synchronous motor 32 here shown asa capacitor startcapacitor run type of motor, the driving coil 33 isconnected to the hot source 12 by wire 34 and to the common return M bwire 35. The auxiliary coil 36 is connected at one side to the wire 34and at the other side to the wire through wire 37, condensor 38. wire39.

The motor 32 is connected to a shaft 40 through the medium of a suitablegear reducer M. The shaft 40 is provided with a driving gear 42. Adriven shaft 43 is providedwith a laterally extending member 44, on theouter end of which is journalled a beveled gear 45. The beveled gear 45is arranged in mesh with the driving gear 42 and with a driven gear 46associated with a spur move through a predetermined arc.

gear 41. The gears M3, 41 are integral or tied together and both arefreely rotatable upon the shaft 43. The shaft 43 is provided with theconventional cams for operating the switches in the traffic signalcircuit. The cams and switches arenot shown inasmuch as they may be ofany conventional construction as used on ,all traffic signal timers. Theshaft .153 is also provided with a dial 48 and an offset arm 49 whichmay be adjusted circumferentially around the dial 2418 and which iscooperable to move a movablecontact 56 into engagement with a contact.51., this structure constituting part of the resynchronizing mechanismto maintain thesecondary timer in step with the master timer.

It will be apparent that unless the gears 46, 41 remain stationary, themotor 32 will not effect rotation of shaft 43 because of the planetaryor compensating gearing 42, 45, 45. If the gears .46,

4 this maximum speed which, in effect, produces an increase in the totalperiod of the traific signal displayed, this because the cam shaft 43 isreduced in speed.

For example, assume that the motor 32 and gearing 4| is effective todrive the shaft 43, whenthe-gears46,--r41.are stationary ate speed of 1.RJP. M. Thismeans=thatthe shaft it-moves 6 per second. Assume now thateach time one of the coils 58, 59, 60 is energized, the motor 55,through thegearing 51, 41, sets the shaft 33 back of 1. It will thentake the shaft 43 one-eighth 'of a second to regain this lost traveleach time a coil-of motor 55 energized. Therefore, if the 'motorj-55receives eight impulses, one second has been added to-thetime requiredfor the shaft 43 to make one revolution. It is apparent that with eachrevolution of the shaft IS, the motor 55 41 are maintained stationary,the motor 32 will 29 drive the shaft 453 at a predeterminedspeeddepending upon the speed of the synchronous motor, the reduction ofthe gearing 4 l, and the ratio of the compensating gearing.

The secondary timer also includes an electroresponsive device cooperablewith the compensating gearing to vary the speed at which the motor 32operates the timer shaft t3. As here shown, the .electro-responsivedevice is in the nature of a second motor 55 operativel connected toshaft 56 provided with a gear 51 arranged in mesh with the gear .41. Themotor 55 is of the impulse type. As here shown, it is provided withthree energizing .coils 5.8, 59, 60. When any one of the coils ,58, 59.60 is energized, the motor is caused to Corresponding sides of all ofthe coils are connected .to the common return 54 through wire 6!,contact 62, relay armature 63, wire 65. The opposite side of the coil 58is connected to the contact 29 through wire 65. The opposite side of thecoil 59 is connected to the contact 3%) through wire 66, and the coil isconnected to the contact 3| through wire 51. Each of the master timercams 23, 24, is so formed as to permit the movable contacts 26, 21, 28to engage the respective stationary contacts 29, 30, 3 1, while themovable contacts engage the low portions 68, 65, 1B of the cams 23, 24,25 respectively. The contacts 26, 21, 28 are connected to the hot feedl2 by wire 1|. These cams are so arranged on the shaft l6 as tosuccessively close the contacts, and each pair of contacts remain closeduntil after the engagement of the succeeding pair of contacts, wherebyone of the coils 58, 59, 60 is always energized. As previously stated,upon energization of each of the coils of motor 55, the motor isthereupon rotated through a predetermined arc and then looked in thisposition as long as the coils remain energized. This being the case, inthe absence of any rotation of gear 51, the gear 41 is held stationarypermitting the synchronous motor 32 to rotate the cam shaft 43 at thepredetermined fixed speed. However, any rotation of the motor 55 andaccordingly the gears 51, :21, either adds to or subtracts from therotation of shaft 43, this because of the compensating gearingdescribed. The direction of rotation of the motor 55 depends upon thesequence in which the coils 58, 59, 60 are energized which, in turn.depends on the direction of rotation of the cam shaft 16 by reversegearing l8. However, the motor 32 and gearing 4| may be arranged tooperate the cam shaft 43 at the highest speed required and the mastertimer and motor 55 employed to subtract from receives three impulses.Accordingly, if the shaft [6 is operated at 40 R. P. M. the motor 55will receive one hundred and twenty impulses per minute. This will addfifteen seconds to thettime required for the shaft 43 to complete onerevolution. However, due .to the fact that the shaft has beenperiodicall set back during the minute interval, the total period willnot-only be extended for the fifteen seconds but in "fact-for a slightadditional period of approximatelyfive seconds, whereby the total.period is actually extended'from sixty seconds'to about eighty seconds.

It will be understood that, as is conventional, the master timer willbelocated at headquarters .where the gearing I1, 18 may be convenientlyadjusted by the operator in charge. I

It will also be apparent that .the variable speed transmission 11;22 areadjustable simultaneously and these transmissions, togetherwith therefineing gearingZfl, 2|,function to maintain a'ce'rtain predeterminedratio between the shafts '16, IS. The reverse gearing I8 is employedonly to reverse the progression of the switches 26,21, 28.

As is the custom in systems of this kind, "the secondary timers of thesystem are periodically checked for synchronism with the master timer.Ashore-shown; thisis accomplished flint he following manner. Once duringeach revolution of the shaft 4 3, the contact 50 is moved intoengagement with contact '51 by offset arm '49. If the secondary timer isnot in step with the master at the time the contacts '50, 5| close, thecontacts 12, 13 will not be opened by the lobe '1 4 on cam 15, and relay16 will be energized by the following circuit. Wires 1|, 11, contacts12, 13, wire 18, contacts 5B, 55, wire '19, relay '16, wire 69, to thecommon return 14, the relay 16 being energized, the armature 63 is movedout of engagement with contact 62 thus breakingthe re turn circuit forthe coils of motor 55. Also,jthe armature 8| will be moved intoengagement with contact82 which is connected to one side of coil 35 ofmotor 32 by wire 83. The armature BI is connected to one side of areactor 85, the opposite side being connected to the common return' 14through wire 86. Thus, the reactor 85 is shunted across the condensor38, causing the motor 32 to stop.

With both of the motors 32, 55 stopped, the secondary timer remainsstationary in this position until the contacts 12, 13 are opened,breaking the circuit to relay 16 and permitting the secondary timer toresume operation. If the secondary timer is in step with the master,simultaneously with the closing of the contact 56, 5|, the contacts 12,13 are opened and the secondary timer does not stop or dwell. The offsetarm 49 is adjustable circumferentially of the disk 48 in order tomaintain the desired relative relationship between all of the secondarytimers. This portion of the control having to do with maintaining thesecondary timers in synchronism with the master timer per se forms nopart of this invention.

It will be apparent that the display of the traffic signals may beconveniently varied from headquarters by adjusting the gearing I1, I 8of the master timer which, through the motor 55, either adds to orsubtracts from the speed at which shaft 43 is driven by motor 32.

It will also be apparent that a solenoid operated ratchet and pawldevice can obviously be substituted for the impulse motor 55 and if twoof such devices are employed with the pawls operating in oppositedirections, the structure will function to increase or decrease thespeed of the shaft 43.

What I claim is:

1. A trafiic signal control apparatus for an inter-connected signalsystem comprising a master timer and a secondary timer, said secondarytimer including a driving motor, motion transmitting means includingcompensating gearing connecting said motor to the timer, a series ofswitches periodically operable by the master timer in a predeterminedsuccession, an electro-responsive impulse device connected to saidgearing and said device having a series of driving coils, each coilbeing connected in circuit through one of said switches, and said devicebeing cooperable with said gearing as each coil is connected in circuitto vary the speed of the secondary timer.

2. A trafiic signal control apparatus for an interconnected signalsystem comprising a master timer and a secondary timer, said secondarytimer including a driving motor, motion transmitting means includingcompensating gearing connecting said motor to the timer, a series ofswitches periodically operable by the master timer in a predeterminedsuccession, an electroresponsive impulse device connected to saidgearing and said device having a series of driving coils, each coilbeing connected in circuit through one of said switches, and said devicebeing cooperable with said gearing to increase the speed of thesecondary timer when said switches are operated by the master timer insuccession in one direction, and to decrease the speed of the secondarytimer when said switches are operated in succession in the oppositedirection, and means associated with the master timer and operable toreverse the succession of operation of said switches.

3. A tramc signal control apparatus for an interconnected signal systemcomprising a master timer and a secondary timer, said secondary timerincluding a driving motor, motion transmitting means connecting saidmotor to the timer and including compensating gearing, anelectro-responsive device connected to said gearing, said driving motorbeing operable to drive the secondary timer at a predetermined constantspeed while said electro-responsive device is inoperative, meansoperable by the master timer to periodically energize saidelectro-responsive device during each revolution of the secondary timer,and said device being cooperable with said gearing upon eachenergization to vary the speed of the timer a predetermined amount.

4. A trafiic signal control apparatus for an in ter-connected signalsystem comprising a master timer and a secondary timer, said secondarytimer including a driving motor, motion transmitting means connectingsaid motor to the timer and including compensating gearing, switch meansactuated periodically by the master timer during each revolution of thesecondary timer in either of two successions, an electro-responsivedevice connected to said gearing, a circuit connecting said switchingmeans to said electroresponsive device, said electro-responsive devicebeing cooperable when said switching means is actuated in one successionto increase the speed of the timer a pre-determined amount and whenactuated in the other succession to decrease the speed of the secondarytimer a pre-- determined amount, and, means associated with the mastertimer for varying the speed of actuation of said switching means by themaster timer, all whereby the speed of the secondary timer may beincreased or decreased by the master timer.

WALTER M. JEFFERS.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,054,203 Higham Feb. 25, 19131,405,041 Kitsee Jan. 31, 1922 1,577,618 Ford Mar. 23, 1926 1,594,396Weston Aug. 3, 1926 1,684,162 'Irumpler Sept. 11, 1928 2,081,652 Turneret al May 25, 1937 2,199,640 Lenehan May 7, 1940

